Changes in version 0.3.1                        

Correctness pass driven by a code review of the v0.3.0 release. No
breaking changes to the public API.

Bug fixes

  - loglik_binomial() and loglik_bernoulli() now use log1p(-p) instead
    of log(val(1) - p). The old form broke hessian() through these
    likelihoods because the intermediate -.value dispatch could not
    handle a dual-number second operand. The new form dispatches cleanly
    through both value and dual autodiff types and is more numerically
    stable as p approaches 1.
  - loglik_negbinom() no longer silently strips the autodiff graph from
    the r parameter. The old code called get_data(r) inside the binomial
    coefficient sum, which meant dL/dr was wrong for any MLE over r.
  - log_safe() now returns a gradient of 0 (rather than 1/eps) at
    elements where the primal was clamped. Propagating a ~4.5e15
    gradient from a region where the primal is known to be wrong was
    actively misleading optimizers.
  - lrt() now warns when the likelihood-ratio statistic is negative
    (which happens when alt_ll < null_ll, typically due to reversed
    arguments or failed optimization). Previously pchisq(negative, ...)
    silently returned a p-value of 1.

New features

  - fit() gains an nobs argument. Passing it populates nobs(result) and
    makes BIC(result) return a finite value instead of erroring on
    log(NULL).
  - profile_loglik() now computes actual profile likelihood by
    re-optimizing over the nuisance parameters at each grid value
    (warm-started from the MLE), whenever the femtofit was produced by
    the current fit(). Previously it silently returned a quadratic
    approximation based on the stored Hessian (mathematically identical
    to the Wald interval in confint()). The quadratic path remains as a
    fallback for legacy femtofit objects that did not stash the wrapped
    objective.

Internal refactor

  - Introduced accumulate_grad(parent, grad_delta, sign) in R/value.R.
    The scalar-broadcast gradient-reduction pattern that was copy-pasted
    through +.value, -.value, *.value, /.value, and ^.value now lives in
    one helper. About 60 lines of duplicated boilerplate removed with no
    change in behavior (covered by existing tests).
  - Deleted log1p_safe's three redundant S3 methods. It is now a
    one-line alias for log1p(), which is already numerically stable and
    has autodiff methods registered by femtograd. No deprecation warning
    emitted.
  - Removed a 10-line dead comment block inside loglik_weibull() that
    documented an implementation path rejected during development.

Tests

  - Added tests/testthat/test-fixes-v0_3_1.R with 13 regression tests,
    one per fix, each documenting the exact pre-fix behavior it guards
    against.
  - Package test count: 820 to 846. Coverage: 89% to 90.6%.

                        Changes in version 0.3.0                        

Initial statistical-inference release. See git history for details.